Electrochemistry Quiz

FR9 - c In the expanded view of the center of the salt bridge shown in the diagram below, draw and label a particle view of what occurs in the salt bridge as the cell begins to operate. Omit solvent molecules and use arrows to show the movement of particles. Nice shapes Lauren

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FR9 A student is given a standard galvanic cell, represented above, that has a Cu electrode and a Sn electrode. As current flows through the cell, the student determines that the Cu electrode increases in mass and the Sn electrode decreases in mass. a Identify the electrode at which oxidation is occurring. Explain your reasoning based on the student's observations.

▪ Sn is oxidizing because it is losing electrons which results in the ionization of Sn to Sn+2 which dissociates from the metal and results in a decrease in the mass of the electrode.

FR9 - b As the mass of the Sn electrode decreases, where does the mass go?

▪ The mass going into the Sn(NO3)2 solution as Sn ionizes to form Sn+2.

1 According to the information above, what is the standard reduction potential for the half-reaction M3+(aq) + e- --> M(s)?

◦ A. -1.66 V

3 Zn(s) is used to reduce other compounds in chemical reactions. If a chemist needs a substance that is more effective in its reducing ability, which of the following species would be the best choice?

◦ A. Na

6 What is the standard cell potential of galvanic cell Z?

◦ B. 0.78 V

4 An electric current of 1.00 ampere is passed through an aqueous solution of Ni(NO3)2. How long will it take to plate out exactly 1.00 mol of nickel metal?

◦ B. 193,000 sec

2 In all electrochemical cells, the process that takes place at the anode is ______________ and the process that takes place at the cathode is ______________.

◦ B. Oxidation, reduction

5 According to the standard reduction potentials given above, what is the standard cell potential for the reaction represented below? 3Ag+(aq) + Al(s) --> 3Ag(s) + Al+3(ag)

◦ C. +2.46 V

7 In galvanic cells Y and Z, which of the following takes place in half cell 3?

◦ C. Reduction occurs in cell Y, and oxidation occurs in cell Z.

8 If the half cell containing 1.00 M Fe(NO3)2(aq) in galvanic cells Y and Z is replaced with a half cell containing 5.00 M Fe(NO3)2(aq), what will be the effect on the cell voltage of the two galvanic cells?

◦ C. The voltage will increase in cell Y and decrease in cell Z.